This invention relates generally to segmented web feeder apparatus and more particularly to a chain drive or sprocket feed assembly for feeding computer printout form webs over a copyboard to the original document platen of a copying machine.
With the widespread use of computers for storing and retrieving information, the need for inexpensive copies of computer printout webs has increased. To produce such copies, electrostatic and the like copiers are being employed.
Because manually feeding the web, segment by segment to the original document platen of a copier would be time consuming and difficult, apparatus for carrying out the latter on an automatic basis has been provided. One such computer form feed apparatus for use in conjunction with a copying machine for feeding computer printout webs to the original document platen thereof includes first and second feed trays between which a conventional fan fold or segmented web computer printout form is fed. The web passes from the first tray through a chute and then along the upper and lower surfaces of a copyboard overlying the platen. The web passes through a second chute to the second tray located beneath the first tray. A pair of sprocket or chain drive devices provide the direct driving force for the web on the copyboard. The chain drive devices each include an endless chain having a plurality of pins extending outwardly therefrom. The pins are spaced a predetermined distance from each other to match the spacing of apertures provided along the edges of the computer form web. The chain is mounted on spaced sprocket and idler wheels and is driven thereabout by rotation of the sprocket wheel. A drive mechanism coupled to the sprocket wheel drives the chain along its path.
A more detailed description of the chute arrangement and drive mechanism employed in the computer form feed apparatus described can be obtained from co-pending U.S. patent applications Ser. Nos. 577,704 and 577,703 entitled Improved Guide Chute Arrangement for Web Feeding Apparatus and Drive Mechanism for Computer Form Feeder Apparatus, respectively, filed the same date as the subject application and assigned to the same assignee.
In the computer form feed apparatus described heretofore, it was found that in transporting standard computer form webs along the copyboard by insertion of the moving pins of the chain drive into the spaced apertures provided along the edges of the web, the web tended to follow the pins even as the left the horizontal path to be carried about the peripheries of the sprocket and idler wheels. Because the pins extend angularly from the chain as the pins are carried about the sprocket or idler wheels, the distance between the free ends of the pins increases. As such, a tearing of the web adjacent the apertures often occurs. Once the web is torn, it is difficult to feed properly thereafter and as such, alignment of the web segments on the copy platen likewise becomes difficult.